PRV camshafts etc.
Ad infinitum, two words from my last post.
Thanks for the refresher course on the evolution of the PRV6.
The technical description of the V6's having long been burnt into my mind after spending the years from 1973 to 1995 earning a crust as a mechanic with the main Volvo dealers in Perth, Adelaide and London.
I must take up on your reasons for the early V6 having different ign. timing for each cylinder bank with the intention of getting it to run smoothly.
The ignition was set up like this in order to match the sequence of the pistons arriving at or near top dead centre. It certainly wouldn't run smoothly if the ignition was arranged evenfire. I'm not being facetious here.
Various other ideas were implemented to even out the intake pulses. The "octopus" inlet manifold was later changed to a "log" manifold with the addition of a vacuum pump for the brake booster, so there must have been some strange goings on with this motor. There were two manifold balance screws on the log manifold, one was screwed out 5 turns the other 1.5 !
When the later "staggered crank" 280e V6 came along the ignition timing was changed, even fire, because the crank design meant the piston travel sequence was altered along with the cam timing as mentioned in my earlier post.
I am calling barleys on this subject otherwise ad infinitum will take over. :wink2:
Feel free to chat among yourselves
pugrambo said:
Ad infinitum, two words from my last post.
Thanks for the refresher course on the evolution of the PRV6.
The technical description of the V6's having long been burnt into my mind after spending the years from 1973 to 1995 earning a crust as a mechanic with the main Volvo dealers in Perth, Adelaide and London.
I must take up on your reasons for the early V6 having different ign. timing for each cylinder bank with the intention of getting it to run smoothly.
The ignition was set up like this in order to match the sequence of the pistons arriving at or near top dead centre. It certainly wouldn't run smoothly if the ignition was arranged evenfire. I'm not being facetious here.
Various other ideas were implemented to even out the intake pulses. The "octopus" inlet manifold was later changed to a "log" manifold with the addition of a vacuum pump for the brake booster, so there must have been some strange goings on with this motor. There were two manifold balance screws on the log manifold, one was screwed out 5 turns the other 1.5 !
When the later "staggered crank" 280e V6 came along the ignition timing was changed, even fire, because the crank design meant the piston travel sequence was altered along with the cam timing as mentioned in my earlier post.
I am calling barleys on this subject otherwise ad infinitum will take over. :wink2:
Feel free to chat among yourselves
ucatis are a very smooth running bike and use a 90 degree V-twin.No primary vibration and secondary vibration is reduced to 35%.Triumph Tridents are a smooth running bike and use an in-line triple with a 120 degree crank.The only vibration from this layout is due to the rocking couple on the crank.If you put these two together into a 90 degree V6 there should be bugger all vibration.Basically only that due to the rocking couple,which is unavoidable in a V6 anyway.
affordable........They conveniently come with a pair of heads with Valves bigger then Volvo fitted in the B-280 along with intake ports that do not have the 'Swirl' feature that Volvo used to choke the B-280 to 140 horses so that it wouldn't be faster then the Turbo-4 that was offered alongside it. Lord knows that Volvo just could NOT have the Frenchie V-6 go faster then the turbocharged tractor mill!! :nownow: 
